The proposed investigation will evaluate the feasibility of performing a total colectomy and mucosal proctectomy, retaining the rectal muscle and anal sphincter mechanism, followed by endorectal ileal pullthrough with ileoanal anastomosis and construction of an intra-abdominal (pelvic) ileal reservoir for fecal storage. The operation will be performed on adult mongrel dogs with construction of a proximal cutaneous ileostomy to divert the fecal stream while the ileoanal anastomosis and the ileal reservoir heal. Different size reservoirs will be constructed to determine the optimal size. A transcutaneous catheter will be placed into the reservoir for decompression, to permit evaluation of bacterial flora, to evaluate electrolyte, water, and various protein, fat, and carbohydrate uptake, as well as to permit a route for evaluation of storage capacity, and ability of the animal to retain liquid or air contents. Manometric studies of anal sphincter function will be performed at varying intervals postoperatively. Intravenous hyperalimentation will be provided during the first 1-2 weeks via a Broviac catheter. Intestinal continuity will be restored by closing the ileostomy at varying intervals from 6-12 weeks after construction of the reservoir. The effects of varying diet composition, use of bulk forming drugs (Metamucil), and use of drugs to slow intestinal motility (Lomotil) will be evaluated. Cultures of the ileal reservoir and biopsy of the mucosa will be obtained at varying intervals to determine chronic changes and need for local antibiotic therapy. The investigation will also evaluate the feasibility of chemical (silver nitrate, sodium hydroxide, etc.) or curettage (mechanical, electrocautery) techniques of removing the rectal mucosa since in patients with advanced colitis it is difficult technically to separate the rectal mucosa from the rectal muscle. The fate of rectal segments from which the mucosa has been removed will be evaluated by clinical examination and by histologic sections. This aspect of the study may have application for patients with sufficiently severe rectal inflammation that would preclude endorectal ileal pullthrough.